1. Field of the Invention
The present invention relates to a timepiece using a spring as power, and more particularly to a power accumulation structure therefor. The timepieces using a spring as power include a mechanical timepiece adapted to move a pointer, which is supported on a wheel train, by utilizing the mechanical energy of a spring, and an electronically controlled type mechanical timepiece. The electronically controlled type mechanical timepiece is like the timepiece disclosed in JP-A-2000-2773, in which a pointer supported on a wheel train is moved by converting the mechanical energy of a spring being unwound into electric energy, and controlling a value of a current, which flows in a coil of a generator, by operating a rotation control unit by the mentioned electric energy.
2. Description of the Prior Art
A timepiece using a spring as power is provided with a power accumulation structure, i.e. a power reservation structure adapted to indicate a residual cumulative quantity of the spring. A related art power accumulation structure has a complicated construction provided with a planetary mechanism, and is disclosed in JP-A-9-21886, a principal portion of this power accumulation structure being as shown in a sectional view of FIG. 4 and a plan view of FIG. 5.
When a spring is wound up by a ratchet wheel 1 in a related art power accumulation structure, an intermediate planetary gear 5a works as a fixed gear of the planetary mechanism, and the rotation of the ratchet wheel 1 is transmitted to a power accumulation wheel 9 via a rotational transmission mechanism including the planetary mechanism. The power accumulation wheel 9 is turned in a predetermined direction, and has a cumulative power pointer 10 indicating that a cumulative quantity of the spring is increasing. A rotation transmission path formed during a spring wind-up operation extends from the ratchet wheel 1 to the power force accumulation wheel 9 via a planetary transmission wheel 3, a second sun gear 4, a first planetary gear 6a, a second planetary gear 6b, a sun gear 7 and an intermediate power accumulation gear 8.
On the other hand, when a barrel complete 2 is rotated to cause the spring to be unwound, the second sun gear 4 works as a fixed gear of the planetary mechanism, and the rotation of the barrel complete 2 is transmitted to the power accumulation wheel 9 via a rotational transmission mechanism. The power accumulation wheel 9 is turned in the direction contrary to the mentioned predetermined direction, and has the cumulative power pointer 10 indicate that a cumulative quantity of the spring is decreasing. A rotation transmission path formed during a spring unwinding operation extends from the barrel complete 2 to the power accumulation wheel 9 via an intermediate planetary wheel 5, a planetary wheel 6, the sun wheel 7 and an intermediate power accumulation wheel 8. During this time, the planetary wheel 6 orbitally revolves around the sun wheel 7 as the planetary wheel rotates on its own axis.
Thus, in a related art timepiece using a spring as power, a power accumulation structure thereof has a very complicated construction using a rotational transmission mechanism including a planetary mechanism. Therefore, the timepiece has a large number of parts, and needs a large space. The problem to be solved by the present invention is to form without using a complicated planetary mechanism a power accumulation structure of a timepiece using a spring as power.
To solve these problems, the timepiece using a spring as power according to the present invention is provided with a power accumulation structure formed so that a cumulative power pointer is driven and indicates a cumulative quantity of the spring when the spring is wound up, by converting a quantity of a rotation of a ratchet wheel into a quantity of a forward linear movement thereof by a threaded mechanism including an externally threaded wheel and an internally threaded wheel, converting a quantity of a rotation of a barrel complete when the spring is unwound, into a quantity of a reverse linear movement thereof, and converting the quantities of the linear movements into those of rotations by a relative movement conversion mechanism.
To be more concrete, the timepiece using a spring as power according to the present invention, which solves the above-mentioned problems, is provided with a power accumulation mechanism including a ratchet wheel for winding up a spring constituted as power for the time piece; a barrel complete mounted on the same shaft as the ratchet wheel, and rotated in accordance with a release of the spring; an externally threaded wheel having an externally threaded portion and a gear portion, and disposed so that the externally threaded wheel is meshed at the gear portion thereof with the ratchet wheel; an internally threaded wheel having an internally threaded portion meshed with the externally threaded portion of the externally threaded wheel, a gear portion and a conical portion, and disposed so that the internally threaded wheel is meshed at the gear portion thereof with the barrel complete; a power accumulation wheel having a cumulative power pointer fixed thereto, and a locking arm engaged with the conical portion of the internally threaded wheel; and a spring member adapted to urge the locking arm of the power accumulation wheel against the conical portion of the internally threaded wheel.
In the timepiece using a spring as power according to the present invention, the threaded mechanism including the externally threaded wheel and internally threaded wheel is adapted to convert a quantity of a rotation of the ratchet wheel into a quantity of a perpendicularly downward linear movement of the internally threaded wheel when the spring is wound-up, and convert a rotational quantity of the barrel complete into a quantity of a perpendicularly upward linear movement of the internally threaded wheel when the spring is unwound.
The conical surface of the internally threaded wheel and the locking arm of the power accumulation wheel constitute a mechanism for converting the quantities of the linear movements into those of movements of rotations thereof. A distance between a point at which the locking arm is engaged with the conical surface of the internally threaded wheel and an axis of the externally threaded wheel varies in proportion to a quantity of a vertically linear movement of the internally threaded wheel. Namely, a quantity of a vertically linear movement of the internally threaded wheel is converted into that of a horizontally linear movement of the point at which the locking arm is engaged with the conical surface of the internally threaded wheel. The locking arm is joined to the power accumulation wheel. Therefore, when the locking arm is moved linearly in the horizontal direction, the power accumulation wheel is rotated accordingly in proportion to the mentioned linear movement of the locking arm. Thus, the quantity of a horizontal linear movement of the point at which the locking arm is engaged with the conical surface of the internally threaded wheel is converted into that of a rotational quantity of the power accumulation wheel.
A surface of the conical portion of the internally threaded wheel is a smooth surface, and a free end of the locking arm of the power accumulation wheel is frictionally engaged with the surface of the conical portion of the internally threaded wheel.
In the timepiece using a spring as power according to the present invention, the surface of the conical portion of the internally threaded wheel is provided with a helical groove, and a free end of the locking arm of the power accumulation wheel is engaged with the helical groove of the surface of the conical portion of the power accumulation wheel.
The timepiece using a spring as power is provided with a power accumulation structure including a ratchet wheel for winding up the spring constituted as power for the timepiece; a barrel complete mounted on the same shaft as the ratchet wheel, and rotated in accordance with a release of the spring; an externally threaded wheel having an externally threaded portion, a gear portion and a stopper surface, supported on a wheel train receiving member and a plate, and disposed so that the gear portion and ratchet wheel are meshed with each other; an internally threaded wheel having an internally threaded portion meshed with the externally threaded portion of the externally threaded wheel, a gear portion and a conical portion, and disposed so that the gear portion is meshed with the barrel complete; a power accumulation wheel having a cumulative power pointer fixed thereto, and a locking arm engaged with the conical portion of the internally threaded wheel; and a spring member adapted to urge the locking arm of the power accumulation wheel against the conical portion of the internally threaded wheel, the timepiece being formed so that forward and reverse linear movements of the internally threaded wheel are restricted respectively by the stopper surface formed on the externally threaded wheel and a stopper surface formed on the plate.
A transmission ratio of the externally threaded wheel with respect to the ratchet wheel and that of the internally threaded wheel with respect to the barrel complete is set equal. This is the condition for miniaturizing the constituent parts of the threaded mechanism and those of the mechanism for converting the quantities of linear movements into those of rotations; and minimizing the number of the parts.